Study of the Pyrimidine Nucleobase C5—C6 Bond Reactivity under Thio-Michael/Aldol Tandem Reaction Conditions.

ChemInform ◽  
2007 ◽  
Vol 38 (1) ◽  
Author(s):  
Edna Vazquez Velez ◽  
Celine Desnous ◽  
Pascale Clivio
Keyword(s):  
Tandem Reaction ◽  
Reaction Conditions

Practical Synthesis of Functionalized Chromeno[3,4-c]pyridine Derivatives via a CuCl2-Catalyzed Tandem Reaction of the Blaise Reaction Intermediates and 3-Cyanocoumarins

Synlett ◽  
2018 ◽  
Vol 29 (07) ◽  
pp. 959-963
Author(s):  
Jian-Jun Li ◽  
Zhiwei Chen ◽  
Yangyang Fan ◽  
Lei Zheng ◽  
Zhaohai Yang
Keyword(s):  
Michael Addition ◽  
Functional Group ◽  
Tandem Reaction ◽  
Pyridine Derivatives ◽  
Reaction Intermediates ◽  
Reaction Conditions ◽  
Purification Technique ◽  
Aromatization Reaction ◽  
Oxidative Aromatization ◽  
Practical Synthesis

This work discloses a novel and efficient protocol for the construction of functionalized chromeno[3,4-c]pyridine derivatives from the Blaise reaction intermediates and 3-cyanocoumarins through a CuCl2-catalyzed sequential Michael addition/intramolecular cyclization/oxidative aromatization reaction. This new method shows the advantages of mild reaction conditions, easy workup, nonchromatographic purification technique, good functional group tolerance, and moderate to good yields.

scholarly journals Efficient synthesis of dihydropyrimidinones via a three-component Biginelli-type reaction of urea, alkylaldehyde and arylaldehyde

2013 ◽  
Vol 9 ◽  
pp. 2846-2851 ◽  
Author(s):  
Haijun Qu ◽  
Xuejian Li ◽  
Fan Mo ◽  
Xufeng Lin
Keyword(s):  
Molecular Iodine ◽  
Tandem Reaction ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Type Reaction ◽  
Reaction Proceeds ◽  
Phosphoric Acids ◽  
Substituted Urea

A one-pot three-component synthesis of dihydropyrimidinones via a molecular iodine-catalyzed tandem reaction of simple readily available mono-substituted urea, alkylaldehyde, and arylaldehyde has been developed. The reaction proceeds with high chemo- and regioselectivity to give highly diverse dihydropyrimidinones in reasonable yields under mild reaction conditions. Moreover, the first catalytic enantioselective version of this reaction was also realized by using chiral spirocyclic SPINOL-phosphoric acids.

Study of the pyrimidine nucleobase C5C6 bond reactivity under thio-michael/aldol tandem reaction conditions

2006 ◽  
Vol 43 (4) ◽  
pp. 1095-1098 ◽  
Author(s):  
Edna Vázquez Velez ◽  
Céline Desnous ◽  
Pascale Clivio
Keyword(s):  
Tandem Reaction ◽  
Reaction Conditions

Sequential Cu(II)-promoted oxidation/[3 + 2] cycloaddition/aromatization tandem reaction for the synthesis of 2-substituted benzo[f]isoindole-4,9-dione

2020 ◽  
Vol 98 (11) ◽  
pp. 690-696
Author(s):  
Zhang-qi Lin ◽  
Chao-dong Li ◽  
Jun-yi Su ◽  
Wen-jie Niu ◽  
Jian-rong Gao ◽  
...  
Keyword(s):  
Efficient Method ◽  
Tandem Reaction ◽  
Reaction Conditions ◽  
Aryl Group ◽  
Efficient Strategy ◽  
Wide Range

An efficient method for the synthesis of 2-substituted benzo[f]isoindole-4,9-dione derivatives from N-substituted iminodiacetates and quinones via a Cu(II)-promoted oxidation/[3 + 2] cycloaddition/aromatization tandem reaction was reported. This tandem reaction uses a wide range of N-substituted iminodiacetate derivatives that contain the chain-alkyl, cycloalkyl, and aryl group on the N-atom. Based on optimized reaction conditions, the desired product of 2-substituted benzo[f]isoindole-4,9-diones was obtained in moderate to excellent yields. Taken together, the promising results of this research would provide an especially efficient strategy to synthesize polysubstituted pyrroles from easy available starting materials and promoted by cheaper Cu(OAc)2.

scholarly journals Solvent- and ligand-induced switch of selectivity in gold(I)-catalyzed tandem reactions of 3-propargylindoles

2011 ◽  
Vol 7 ◽  
pp. 786-793 ◽  
Author(s):  
Estela Álvarez ◽  
Delia Miguel ◽  
Patricia García-García ◽  
Manuel A Fernández-Rodríguez ◽  
Félix Rodríguez ◽  
...  
Keyword(s):  
Proper Choice ◽  
Tandem Reaction ◽  
Tandem Reactions ◽  
Nazarov Cyclization ◽  
Reaction Conditions

The selectivity of our previously described gold-catalyzed tandem reaction, 1,2-indole migration followed by aura-iso-Nazarov cyclization, of 3-propargylindoles bearing (hetero)aromatic substituents at both the propargylic and terminal positions, was reversed by the proper choice of the catalyst and the reaction conditions. Thus, 3-(inden-2-yl)indoles, derived from an aura-Nazarov cyclization (instead of an aura-iso-Nazarov cyclization), were obtained in moderate to good yields from a variety of 3-propargylindoles.

I2/DMSO-Promoted the synthesis of chromeno[4,3‑b]quinolines through an imine formation/aza-Diels-Alder/aromatization tandem reaction under metal-catalyst and photosensitizer-free conditions

Synthesis ◽  
2021 ◽  
Author(s):  
Angelica Peñaranda ◽  
Carlos Eduardo E. Puerto Galvis ◽  
Mario Alberto Macias ◽  
Cristian Ochoa-Puentes ◽  
Vladimir V. Kouznetsov
Keyword(s):  
Lewis Acid ◽  
Molecular Iodine ◽  
Diels Alder ◽  
Metal Catalyst ◽  
Tandem Reaction ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
Heterocyclic Molecules ◽  
Dmso System ◽  
Tandem Process

A tandem approach was developed for the efficient synthesis of substituted chromeno[4,3-b]quinolines from arylamines and O-cinnamyloxy salicylaldehydes under metal-catalyst and photosensitizer-free reaction conditions. Our protocol is based on an inexpensive I2/DMSO system in which molecular iodine first acts as a Lewis acid to promote the formation of the corresponding imine bearing the alkene moiety, then, this species fulfills a second role by catalyzing the intramolecular aza-Diels-Alder cycloaddition to generate the respective tetrahydro-chromenoquinolines as an intermediates. Finally, the dual behaviour of DMSO as an oxidant and as a solvent resulted crucial at this stage, allowing the regeneration of I2 and promoting the aromatization of the tetrahydro-chromenoquinoline intermediates to yield the desired 7-aryl-6H-chromeno[4,3-b]quinolines. This protocol features by being mild, easy to perform, high step-economy (tandem process) and for providing a new access to biologically important nitrogen and oxygen containing heterocyclic molecules.

Efficient method for the synthesis of polysubstituted 2,6-dicyanoanilines by one-pot three-component tandem reaction of malononitrile with α,β-unsaturated imines

2015 ◽  
Vol 69 (7) ◽  
Author(s):  
Wei Chen ◽  
Xiao-Yan Lu
Keyword(s):  
Efficient Method ◽  
Michael Addition ◽  
Tandem Reaction ◽  
Reaction Conditions ◽  
One Pot ◽  
One Pot Synthesis ◽  
High Yields ◽  
The Michael Addition

AbstractA facile and efficient one-pot synthesis of polysubstituted benzenes was achieved via the Michael addition of malononitrile with α,β-unsaturated imines and a sequential tandem reaction. This reaction generates polysubstituted 2,6-dicyanoanilines in high yields (15 examples, isolated yields of 57-91 %), and proceeds under mild reaction conditions (60°C, 10 min). In addition, a possible mechanism accounting for the reaction is proposed.

Undecagold labeling of tRNA

1991 ◽  
Vol 49 ◽  
pp. 44-45
Author(s):  
James F. Hainfeld ◽  
Kyra M. Alford ◽  
Mathias Sprinzl ◽  
Valsan Mandiyan ◽  
Santa J. Tumminia ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Electron Micrograph ◽  
Anticodon Loop ◽  
Electron Micrograph ◽  
Reaction Conditions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The undecagold (Au11) cluster was used to covalently label tRNA molecules at two specific ribonucleotides, one at position 75, and one at position 32 near the anticodon loop. Two different Au11 derivatives were used, one with a monomaleimide and one with a monoiodacetamide to effect efficient reactions.The first tRNA labeled was yeast tRNAphe which had a 2-thiocytidine (s2C) enzymatically introduced at position 75. This was found to react with the iodoacetamide-Aun derivative (Fig. 1) but not the maleimide-Aun (Fig. 2). Reaction conditions were 37° for 16 hours. Addition of dimethylformamide (DMF) up to 70% made no improvement in the labeling yield. A high resolution scanning transmission electron micrograph (STEM) taken using the darkfield elastically scattered electrons is shown in Fig. 3.

Catalytic enantioselective synthesis of indolizino[8,7-b]indole alkaloid derivatives based on the tandem reaction of tertiary enamides

2021 ◽  
Author(s):  
Xin-Ming Xu ◽  
Ming Xie ◽  
Jiazhu Li ◽  
Mei-Xiang Wang
Keyword(s):  
Indole Alkaloid ◽  
Enantioselective Synthesis ◽  
High Yield ◽  
Tandem Reaction ◽  
Indole Derivatives

An exquisite Pybox/Cu(OTf)2-catalyzed asymmetric tandem reaction of tertiary enamides was developed, which enabled the expeditious synthesis of indolizino[8,7-b]indole derivatives in high yield, excellent enantioselectivity and diastereoselectivity.

Dimensionally-Controlled Hydrothermal Tm3+-doped Oxidic Nanocrystals and Their Photoluminescence Properties

2010 ◽  
Vol 1247 ◽  
Author(s):  
Rocío Calderón-Villajos ◽  
Carlos Zaldo ◽  
Concepción Cascales
Keyword(s):  
Single Crystals ◽  
Fluorescence Lifetimes ◽  
Photoluminescence Properties ◽  
Reaction Conditions ◽  
Hydrothermal Processes ◽  
Bulk Single Crystals ◽  
Template Free ◽  
Reaction Media

AbstractControlled reaction conditions in simple, template-free hydrothermal processes yield Tm-Lu2O3 and Tm-GdVO4 nanocrystals with well-defined specific morphologies and sizes. In both oxide families, nanocrystals prepared at pH 7 reaction media exhibit photoluminescence in ∼1.95 μm similar to bulk single crystals. For the lowest Tm3+ concentration (0.2 % mol) in GdVO4 measured 3H4 and 3F4 fluorescence lifetimes τ are very near to τrad.

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